Anti-offset powder spray and cleaner system



Sept. 11, 1962 D. J. DOYLE" ANTI-OFFSET POWDER SPRAY AND CLEANER SYSTEMFiled March 17, 1960 2 Sheets-Sheet 1 mmmlOI INVENTOR. DONALD J. DOYLEfl/JM ,TM

ATTORNEYS Sept. 11, 1962 D. J. DOYLE ANTI-OFFSET POWDER SPRAY ANDCLEANER SYSTEM Filed March 17, 1960 2 Sheets-Sheet 2 wmaiv INVENTOR.DONALD J. DOYLE k/M W ATTORNEYS 3,053,180 Patented Sept. 11, 19623,053,180 ANTI-OFFSET POWDER SPRAY AND CLEANER SYSTEM Donald J. Doyle,1297 W. 114th St., Cleveland 2, Ohio Filed Mar. 17, 1960, Ser. No.15,681 16 Claims. (Cl. 101-416) The present invention is generallyconcerned with applying anti-offset spray to a printed paper or the likeand the removal of excess sprayed material from the paper; and moreparticularly with the effective application of an anti-offset powder toa moving printed web or sheet in a printing press with a simultaneousremoval or clearing from the sheet of excess powder, while at the sametime preventing spreading of the powder to other parts of the press towhich the system is applied.

The application of a spray powder, that is an anti-offset powder, in aprinting press to a freshly printed sheet or web has in the past beenattended by certain difliculties in the overall printing operation.Since the powder is generally dropped or blown upon a moving sheet orweb, as a practical matter it must pass through some free or unconfinedspace, however small, in its path to the paper.

Apart from the question of the removal of excess powder from the webitself, the airborne powder may be carried by the non-dissipatedcurrents of air by which it is blown, or may even merely drift to otherparts of the press, there to foul the press mechanism and so increasethe maintenance burden; or to the paper itself at more remote regions inits path of press travel. Further all excess powder actually on thepaper must be removed, as required in cleanliness of the printed productand also to avoid transport of the powder by the paper to parts of thepress which would be fouled thereby.

The general object of the present invention is then to provide a meansin a printing press for applying to freshly printed paper, either movingindividual sheets or a continuous web, an anti-offset powder ineifective manner and at the same time to remove all excess from the webor paper. A further object is to provide means for applying theanti-oifset powder and simultaneously removing all excess from thesheet, while preventing air transport of powder from the region ofapplication to other parts of the press. A still further object is toprovide a system for applying anti-oifset powder to freshly printedpaper moving in a press by means minimizing the spread of powder toother parts of the press, thereby to diminish powder-caused wear ofpress parts and as well to diminish maintenance required merely to keepthe press clean enough for satisfactory production.

The means by which these and other objects and advantages of theinvention are achieved will be set forth in the following descriptionand the drawings wherein:

FIG. 1 is a more or less schematic representation of the system showingthe general relation of the system components, and also a suitabledisposition of a powder distributing and cleaning manifold or headrelative to paper transport cylinders in a printing press; and

FIG. 2 shows in greater detail the structure and operation of said head.

In general organization, as shown in FIG. 1, the system comprises theanti-offset distributing and scavenging head A and associatedanti-static bar B, disposed adjacent the sprocket and transfer cylindersC1, C-2 of a printing press to operate on the moving web of paperpassing over -1; an electric motor-driven air pump or centrifugal fan P,drawing air from the surrounding atmosphere to supply the head A;preferably, a dual heater with separate halves H-1 and H2 included inthe respective air duct branches D1 and D-Z leading from the outlet ofthe pump; an anti-offset powder storage and dispensing hopper unit G forintroducing the powder through a powder 0 the head mixing and feedcontrol valve G-l into the air stream in D1 to be carried thereby to thehead; and an electric motor driven exhaust air pump E drawingpowder-laden air from the head through exhaust duct D-3 to pump the samethrough a dynamic precipitator S for separation and recovery for re-useof powder before venting of the air to free atmosphere. Valves V-1, V-Zbefore the heater and V-3 before the exhaust pump are provided in thecorresponding ducts to regulate and balance air flow and pressure in thesystem as required for operations hereafter detailed.

The general form and disposition of headA is apparent in FIG. 1 andfurther details of construction in FIG. 2. In the head a pair ofirregularly shaped end walls or plates 10, a top wall plate 11; a rearwall plate 12; a pair of three-quarter cylindrical elements 13, 14secured respectively in parallel spaced relation to the inside of thebottom edges of plates 11, 12 and to front and rear edges of a bottomplate 15, form a main housing structure of the head extendingsubstantially the full length of the cylinders.

An internal partition 16, running from end to end of the housing inspaced relation to wall 11 and having a forward edge secured to member13, at its rear is carried up into a dome structure 17, here likewise inspaced relation to the forward dome Wall 17a to define a spray manifold,an air passage d1 putting a longitudinal series of apertures 13a formedin 13 in communication with duct D1, the back edge portions of 16underlying the wall 11 being curved up to join the latter; an extendedsloping irregular portion 18, cooperating with other partitions,partition 19 and irregular partition 20, sides 17c and top 17d in thedome, in bounding distinct passages.

Similarly an internal partition 19 spaced from the rear wall 12 and domerear wall 17b, with extension 20 defines a cleaning air passage ormanifold putting duct D-Z in communication with the longitudinal seriesof apertures 14a in 14. The remaining free space bounded by the saidpartitions then provides an exhaust air manifold, the larger passagewayd-3 from perforations covering a major part of plate 15 to exhaust ductD3.

The three-quarter cylindrical elements 13 and 14 serve as casings forrotatably mounting spray and cleaner or scavenging air tubes 23 and 24,with series of arcuate kerfs or slots 23s, 24s respectively matchingapertures 13a, 14a, so that by rotational tube adjustment, the directionof air issuing from apertures 23a, 24a to impinge upon the web may bealtered. Friction between a tube and its casing, or positive lockingmeans can be used to hold a tube setting.

A perforated control plate 25 with apertures 25a is slideably adjustablysupported on the inner face of plate 15 (to vary flow through apertures15a and for a given exhaust volume the velocity of the air picked up) bya transverse rod 26 secured along its upper margin and having axiallyprojecting studs at opposite ends extending through slots 27 in plates10 for manipulation and locking by external washers and wing nuts orlike fasteners.

Also for further control of exhaust air flow, a partition 30 runningfrom end to end and extending horizontally rearwardly from 13 leaves anopening between its rear edge and partition 19, which is varied by acontrol or sliding valve structure 31, comprised of a pair of spacedplates 32, 32 slideably sandwiching the rear part of parti- 5 tion 30,and at the rear mutually secured and supported 'by a rod 33, againhaving stud-like projections 34 extend ing through horizontal slots 35in plates 10 for external manipulation and locking.

The anti-static device B is conveniently mounted on A, in proximity tothe moving paper web; and also to the spray tube 23 as shown since thecharges on the spray powder particles will, as well as the web, be

is thereby neutralized for a better application to the printed paper.The particular form of the mounting will of course depend on thespecific type of device used, as known to the art.

The head A is supported from surrounding environmental press structuresuch as parallel lateral press frame members 40 by say a .transversehinge plate ll and a vertical hinge plate 42, through the hinge knucklesof which a long removable rod 42a extend-s as a pintle.

Further to enclose the head at each end (see FIG. 2) a respectivevertical shield plate 43 is provided, removably attached to the endwalls and in close proximity to the ends of the cylinders. Thus suchoutside air as is drawn into the head will enter in greater part underthe front and back tubes, the shield plates serving to reduce the airflow at the end-s, usually in some degree to increase the velocity ofair entering between shields and head ends, and to minimize thereby thepossibility of escape of the powder from the head region to other partsof the press. The air supplying and exhaust fans or blowers P, E, ductwork and valving, the separator S, hopper unit G with feed valve G-1,and heaters H-1 and H2, may be selected from many types of therespective units known to air moving or heating and pneumaticmaterial-conveying arts. Obviously the blowers may be other thanelectrically driven, and the air heater units may transfer heat to theair from electrical, gas, steam or other heat sources, thermostaticallyor manually controlled.

So also the anti-static bar can take the form of many devices known inthe printing or other arts involving moving sheets, webs, tapes or othermaterials, which tend to acquire, troublesome static charges; thepatented arts of which disclose the use of high voltage dischargedevices, radioactive or other sources of ionizing radiation for example,usually with a grounded element even such as a press cylinder contactingthe moving web in a region close to and opposite the bar.

Since the specific forms of these individual units, and individualcontrol means are not per se part of the invention and suitable formsthereof are known to those skilled in the art, such are not heredetailed.

In operation of the system, the valve V1 and feed from hopper G areadjusted to deliver powder through spray tube 23 across the width of theprinted web in sufficient amount to ensure adherence of the same to allyet undried parts of the print; valve V-2 is set to deliver suchquantity of air to the tube 24 as will effectively prevent escape ofair-borne powder from the web, providing an air wall and sweeping thesame toward the middle or exhaust region of the head; while V-3 is setin conjunction with slide-valve members 31 and 25 to draw not only thetotal air volume supplied by 23 and 24 (with entrained powder) into theexhaust system, but usually also some ambient air under the front, rearand sides of the head A as a further air curtain or wall to preventescape of air-borne powder at the latter locations. The setting of 25 isprimarily chosen to limit the capture velocity of the air taken in toavoid picking up too much powder from the paper. On the other handshould need arise, the air from 24 may help to scour from the web powderapplied in excess.

The rotational settings of tubes 23, 24 are adjusted in the firstinstance to direct their respective air streams most effectively, thoughinwardly in any event, for their intended purposesof powder applicationand scouring and 'to minimize tendencies to allow powder carriedtherewith to escape the head, under conditions of a given exhaust airvolume. Thus the powder-laden air from 23 is directed generally in thedirection of web travel; and air from 24 counter to the web travel as anair wall preventing escape of air-borne powder.

The heating of the air delivered through D-l aids the distribution ofthe powder from the hopper to the web, one reason apparently being thatthe powder is thereby dried, tends to disperse the more readily, and anysmall lumps due to moisture content are the more readily broken up; andhlrther heated air delivered through 23 and 24 accelerates drying of theink. The temperature of the air thus delivered for a given volume may beincreased for this purpose. The greater, then, the drying induced at thehead H, generally the lower is the amount of ofi-set powder required.

These various adjustments then may affect one another, but of courseunder normal adjustments are empirically selected preferably to achievethe necessary functions (powder application to, scouring and cleaningfrom the web, and confining of the powder to the head region) with aminimum of air consumption, therefore of energy requirements by thesystem.

Where the oifset powder prevents difficulties consequent to lumping orcaking the hopper feed control G-l preferably will comprise a powerdriven dynamic device; for example including a motor-driven rotary feedroller already known to the patented art for feeding and distributingsuch powder from a supply space, though usual ly directly onto a movingweb; or including a'mechanically or electromagnetically vibratedelement, serving to maintain powder flow.

I claim:

1. A system for applying an anti-offset powder in a printing press to amoving printed web and for minimizing fouling of surrounding structureof the press, comprising: a unitary head structure adapted to bedisposed in the press entirely on one side of the web path for operationupon the web at a localized area therein and including a powderdistributing tube extending transversely across the web, a scavengingair tube parallel to said distributing tube and spaced therefrom in thedirection of web movement, said tubes being proximate to said web andhaving air apertures for directing convergent air streams to impingeupon the moving web across the transverse extent of the web, the spacingof said tubes delimiting the area of localized operation of the saidhead, the head also including means for applying a vacuum for exhaustingpowder-laden air from the space between said tubes; continuous vacuumproducing means connected with the last :said means; means forcontinuously supplying air to the said tubes; and powder supply meansfor introducing anti-offset powder to air supplied to the distributingtube.

2. A system as described in claim 1, including means disposed adjacentthe path of said web before said distributing tube for diminishingstatic electrical charges on said web before the web is subjected to apowder-laden air discharged from the distributing tube.

3. A system as described in claim 1, wherein the means for exhaustingthe powder-laden air comprises an exhaust fan connected by duct-work tothe space between said tubes, the space between said tubes and said webbeing confined endwise by shield plates to minimize dispersal of powderto adjacent portions of the press.

4. A system as described in claim 3 including means for regulating theair flow to said tubes from the air supply means, and from said space tosaid exhaust fan.

5. A system as described in claim 1, including means for heating airsupplied to the respective said tubes.

6. A system as described in claim 5, including means disposed adjacentthe path of said web before said distributing tube for diminishingstatic electrical charges on said web before the web is subjected to apowder-laden air discharged from the distributing tube.

7. A system as described in claim 1, including means receiving the airdischarged from the air exhausting means adapted to separate and recoverfrom an exhaust air stream powder entrained therewith.

8. A system as described in claim 1, wherein said tubes are adjustablymounted to vary the angle of impingement of said air streams upon theweb.

9. Apparatus for applying to a moving printed Web in a printing press ananti-offset powder and for minimizing powder fouling of the press,comprising: an operating head mounted in the press in proximity to -anewly printed side of the web; said head including an elongated closedhousing extending across only one side of the web, a pneumaticallysupplied powder distributing tube along an edge of the bead locatedtoward the direction from which the web approaches, and a scavenging airtube in rearwardly spaced parallel relation to the first said tube, saidtubes being apertured to direct air upon adjacent moving portions ofsaid web, an exhaust air intake region between said tubes, and airpassages within said housing from said tubes and intake region torespective external connections of the head; an air supply fan andvalved ducts from said fan to the head external connections of saidtubes for continuously supplying air to said tubes; and an exhaust fanand a valved duct therefrom to the external head connection of saidexhaust region for continuously exhausting air from the space delimitedby said tubes and said web.

10. An apparatus as described in claim 9, wherein said tubes arerotatably mounted in respective casing element-s having air aperturescommunicating with respective said air passages, and said tubes havearcuate slots corresponding to the air apertures and air directingoutlet apertures, whereby the direction of air impinging upon the webfrom the outlet apertures may be varied.

11. Apparatus as described in claim 10, wherein the exhaust air intakeregion between said tubes is spanned by a perforated plate, said platebeing overlapped by a slideable second perforated plated controllingintake of air exhausted into said head.

12. Apparatus as described in claim 9, wherein said head includes aninternal slide valve for controlling air flow from said exhaust airintake region.

13. Apparatus as described in claim 9, including antistatic meansextending across said web forward of said powder distributing tube fordischarging static charges carried by said web.

14. A system for applying anti-oifset powder in a printing press to amoving printed paper, comprising: means for air-spraying the powder onthe moving paper, means for directing air upon the paper to establish anair curtain confining air carrying said powder in a limited space nearthe point of application, the last said means serving to remove excesspowder from said paper, and means for exhausting from said region airentering the same by operation of the first two said means.

15. In a system as described in claim 14, means for neutralizing staticon the paper before powder is sprayed thereon,

16. In a system as described in claim 15, means for heating air utilizedin at least one of the first two said means.

References (Iited in the file of this patent UNITED STATES PATENTS703,466 Prince July 1, 1902 1,558,831 Brunner et al. Oct. 27, 19251,566,800 MacArthur Dec. 22, 1925 1,867,256 Egli July 12, 1932 2,332,385Lauring Oct. 19, 1943 2,479,882 Wallhausen et al Aug. 23, 1949 2,961,952Doyle Nov. 29, 1960 FOREIGN PATENTS 596,540 Great Britain Jan. 6, 1942

